Fuel feeding system



June 3, 1947. L. BEEH FUEL FEEDING SYSTEM Filed Sept. 5, 1941 INVENTOROU/5 @EE/ my i mi?? Patented June 3, 1947 UNITED STATES PATENT OFFICEFUEL FEEDING SYSTEM Louis Beeh, Springfield, Mass. Application'September 5, 1941, Serial No. 409,663 (cl. 12s- 139) 12 Claims. y 1

This invention relates to a fuel feeding system for internal combustionengines of the solid injection type'. In engines of the type to whichthe invention relates an injector directed into the combustion space ofthe engine is provided with an injection valve which is opened inresponse to the increasing pressure of. the -liquid fuel suppliedthereto by a suitablejfuelpump and is closed by the action of a heavyspring or other resilient means in response to a reduction of pressurein the fuel supply line. This de` crease in injection pressure isnormally the result of the opening of a spill valve or by-pass passagewhich opens into the pressure chamber of the pump and therebyimmediately and sharply reduces the pressure in this chamber. Because ofthe high pressures of the order of 4000# per square inch in the Afuelline there is a reaction of this pressure in the direction of thereduced pressure in the pump chamber and a resultant tendency ofthe fuelin the line to reverse its direction of flow 'and move in the directionof the pump chamber. The reaction causes the discharge valves betweenthe pump chamber and the fuel line to close sharply s 'that the fuel inthe injection line is still under a'high pressure.

Reactions are set up due to the inertia of the moving column of fuel anddue to the natural resilience 'of the supply line, such that reversalsof the pressure wave in the supply line are set up so that the waveagain moves in the direction of the injection valve, tending to open thesame slightly and causing a slight dribble at the nozzle orice.

The fuel so improperly atomized and improperly timed with respect to theengine cycle is not properly consumed andv is therefore objectionablefrom the standpoint of thermal eiliciency, but it also tends tccarbonize around the nozzle orifice and is therefore also objectionablefrom the point of view of mechanical efficiency.

In some instances these pressure waves travel back and forth severaltimes in the fuel line, causing no t only secondary Lut tertiaryinjections.

There have Aheretofore many attempts made to overcome theabove-mentioned difficulty and prevent thisvdribble at the fuel nozzle.The most common of these is to provide a skirt 'on the discharge valveof the pump. which skirt upon the closure of the valve functions as apiston or plunger, moving in the direction of the pump chamber, and istherefore effective to increase the total volumetric capacity of thefuel line and other connections between the pump chamber and theinjection nozzle. Such a system is effective to reduce the staticpressure within the fuel line and therefore avoid any oozing of y fuelfrom the nozzle due to this static pressure.

Such a system, however, is not effective to reduce the dynamic forceswhich cause the secondary and tertiary injections which are due tosuccessive reversals of the direction of flow in the line, which occurupon the final closure of the discharge valve whether provided with yawithdrawal skirt or not, due to the piling up of the pressure in thevicinity of the discharge valve and the reaction of this pressure backthrough the line in the direction of the injection valve.

It is among the objects of the present invention to overcome theabove-mentioned diflculties and prevent the violent oscillations of theAiuel remaining in the fuel column.

The secondary and tertiary injections abovedescribed leave the fuellines, if they are not all of the same capacity, under varying residualpressures and cause the next succeeding injecboth the beginning and theend of the injection,

thereby providing a smoother engineoperation.

The above and other objects and features 0f the invention will beapparent to those skilled in the art from a consideration of thefollowing detailed description vtalren-in conjunction with theaccompanying drawings in which:

Fig. 1 is a vertical section of a portion of the fuel feeding deviceconstructed in accordance with the present invention and also showing aportion of the internal combustion engine to which the device isconnected.

Fig. 2 is a vertical section through a portion of a-fuel feeding deviceshowing a modied form of the invention.

Fig. 3 is a view similar to Fig. 2 to show a further modification.

Referring to the drawing, reference numeral I roundingthe'valve on thepermit the escape rected into the combustion space 4. The nozzle orice 3is closed by a valve 5 of conventional construction and having as usuala shouldered portion 6 which is adapted to be acted upon by the pressureof fuel supplied thereto by way of the supply line 1 to move the valvein an opening direction against the action of the spring 8.

luel is supplied to the injector .2 by means of a pump 3 havinga plungerI0 mounted to reciprocate in a cylinder II and adapted to uncover asupply port 12in its lowermost position whereby fuel from the feedchamber I3 may ilow into the pump ch mber I4 when piston I0 is in theposition show'n in the drawing, while the upper end of the cylinder IIis closed by a plate I5, which plate is provided with a dischargeorifice I6 provided in the central portion thereof. The plate I=is heldin position against an interior shoulder in the pump body I1, and alsoagainst the upper end of the pump cylinder I I, by means of a bushing I8which is provided with external 'threads coacting with'internal threadsin the upper end of the pump body I1 to the end that an annular boss I9upon the end of the bushing I8 will press upon the peripheral portion ofthe plate I5 when the parts are in the position shown.

The bushing I8 is provided with a central cylindrical bore 20 in which adischarge Valve 2| having a cylindrical sleeve portion 22 is adapted toreciprocate, being biased in the direction of plate I5 by the spring 23.The lower end of the valve 2I is provided with an annular bossf24 ofconsiderably less external diameter than the external diameter of thesleeve portion 22. The annular boss 24 is adapted to seat upon the plateI5 in closing relation to the orifice IB sothat when the valve is in theclosed position, as shown. a relatively small area thereof is exposed tothe pressure within the pump chamber I4, while an additional ar'ea isexposed to the pressure of the fuel in the annular discharge chamber 25surdischarge side of the oriflce'f- I-E.1"

The chamber 25 communicates by way of passages' 26`in the bushing I8with an annular chamber 21; which chamber is directly connected to thefuel supply line 1. For convenience of construction'the annular chamber'21 may be formed 4 I0 approaches the end of its discharge stroke, ahelical lip 34 on the end of the plunger II) uncovers the by-pass port33, permitting the fuel from the pump chamber I4 to flow into the bypasschamber 35 and thence back to the fuel supply tank by way of pipe 36;thus there is a sharp reduction in the pressure within the pump chamberI4 and within the discharge chamber 25. The pressure in the supply line1 is sharply reduced, the injection valve 5 tends to close and the fuelin the supply line '1 which was formerly owing at high velocity towardthe injection valve now tends to iiow in a reverse direction toward thefuel pump. This -reversal of flow sets up a pressure wave in thedirection of the pump which, if the discharge valve 2I were aconventional check valve, would tend to cause the valve to seat sharplydue no t only to the action of the spring :23 but also to the dynamicpressure of the fuel in the supply line. This would be true regardlessof whether or not the check valve were provided with a withdrawal skirt.

By the present construction the reversal of flow in the supply line 1has no tendency to close the discharge valve but on the contrary actsupon the valve to move the same in an opening direction so that thepressure wave tends to become dissipated through the discharge orice I6,the pump chamber I4 and thence to the by-pass port 3-3. Thus thereversal of :dow in the fuel line does not build up a pressure on thedischarge side of the valve which could possibly react back in thedirection of the injection valve and cause a secondary injection. Itwill be understood that the spring 23 being weaker than the spring8,-any pressure wave present in the fuel line and hav- -ing sufficientforce to open either of the valves,

will necessarily dissipate itself through the discharge valve of thepump ratherl than through in a block 28 separate from the bushing I8 andrmly attached thereto in a manner hereinafter to be described. h

The valve spring 23 is adjustable by means of a screw plug 29 whichextends through an internally and externally 'threaded nipple 30 whichprojects from the upper end of the bushing I8. The screw plug 29has acentral passage 3l to of any fuel which leaks around the valve 2l intothe cylindrical bore 20. A nut 32 coacting with the external threads onthe nipple 3D holds the block 28 firmly in position.

In the operation of the device when the parts are in the position asshown, with the plunger lllin its lowermost position, fuel is suppliedunder some pressure by Way of the supply chamber I3, and the pumpchamber I4 is filled with fuel. As the plunger I8 moves upwardly theintake port I2 as well as the by-pass port 33 are closed by the upperedge of the plunger II] and further upward movement vof the plunger I0places the fuel under .suiiicient pressure to cause the same to lift thethe injection valve of the engine.

Referring to Fig. 2 which shows only the parts directly associated witha modif-led form of the discharge valve, it will be obvious from thedrawing that the construction and operation of this form is closelyanalogous to the form shown in Fig. 1 except that a small valve 4Il isprovided in the discharge valve 4I and is adapted'to control an orifice42 which extends through the face of the discharge valve 4l. As in theprior construction a spring 43 biases the discharge valve 4I in aclosing direction' and a spring 44 surrounding a stem 45 on the valve 40normally maintains the latter valve in a closed position. A set screw 46is mounted for adjustment in the upper closed end of valve chamber 41and projects downwardly therefrom to contact with the' upper end of thestem 45 of the valve 40 whenever the discharge valve 4I has been liftedto a point slightly below the uppermost limits of its opening movement.

The operation of the form shown in this figure is similar to theoperation of the form shown in I Fig. 1 since it will be understood thatfuel placed under pressure by the pump plunger will lift the dischargevalve 4I from its seat and cause fuel to ow to theengine by Way ofpassage 48, the cutoif of the fuel supply and the prevention ofoscillations of fuel in the fuel line being effected in the same manner.The form here shown, however, has the additional advantage that at highspeeds the valve 4I moves upward further in its opening direction thanat low speeds and as these high speeds are attained the stem 45 of thevalve 40 contacts the set screw 46, thereby Ipermitting a slight flow offuel through the passage 42 into pressure stroke thereof tends `toincrease as the speed increases. This is particularly true in connectionwith pumps of the type in which the quantity of the fuel supplied by thepump is controlled by a helical lip on the end of the plunger, which lip'varies the time of opening and closing of the by-pass passages of thepump to the end that angular movements of the pump plunger will causethe by-pass passage to be opened sooner or 'later during the dischargestroke of the pump plunger and accordingly supply a smaller or greaterquantity of fuel to the engine for each working stroke thereof. In allsuch constructions where one or more of the ports of the pump arepositioned in the side walls of the pump cylinders and controlled by theplunger, the leakage around the plunger into these ports will be greaterwhen the pump plunger is moving slowly thanit will be when the pumpplunger is moving at high speed. For this reason the pump will tend tosupply a greater charge at high speed for cach stroke thereof than itwill supply when operating at a relatively low speed.` This increase inthe unit charge of fuel supply at high speeds is' the reverse of therelationship that is actually required inasmuch as a slight reduction inthe unit charge for high speeds is desirable. l;

By the form of the invention disclosed .in Fig. 2 an automaticcompensation is made for the unit charge supplied by the pump at highspeed since at low speed the discharge valve 4| ds not move upwardly farenough for the stem 45 to contact with the set screw 46 and thereforethe full charge for any given setting of the control rod of the pump issupplied to the combustion-space of the engine. However, as high speedsare attained the valve 4| moves further in its opening direction untilthe valve 40 is opened by contact of the end of stem 45 against the setscrew 46 and a slight compensating leak-v age is thereby permittedduring the short period in which the discharge valve 4|` is in itsuppermost position. t A

It will also be seen that this form of the invention provides a safetyescape in the event that the fuel nozzle 3 should become clogged or theinjection valve 5 should become stuck so that fuel cannot be dischargedinto the clearance space of the engine, for in either case pressurescannot be built up in the fuel line 'l such as would cause breakage ofthe pipes or connections because under such conditions-the valve 4|would be forced to its uppermost position, causing the valve 40 to openand relieve the pressure in the fuel line by way of the orifice 42,the-valve chamber 41 and return passage 49.

Referring to the form shown in Fig. 3 it will be seen that theconstruction is similar to that shown in Figs. 1 and 2, except that thedischarge valve 50 is provided with an enlarged shouldered portion 5| ofgreater diameter than the sleeve portion 52 of the valve and that thisenlarged portion on the Avalve makes a loose sliding t with a slightlyenlarged portion 53 'of the cylindrical bore 54. As in the constructionpreviously described, the valve 50 is adapted to close the dischargeport 55 ofthe pump chamber i6 to permit the now of fuel to the engineduring the discharge stroke of the pump plunger. the fuel passing by wayof vertical passages 5l and cross passages 58 to the discharge nipple 59which is connected to the fuel supply lin'e leading to the engine`cylinder asndisclosed in Fig. l.

However, in this construction the valve chamber 60 is connected directlyto the fuel supply line by way of an orifice 6| connecting with crosspassage 58 at a point which is preferably in `line with the passagethrough 'thedischarge nipple -59 which is connected to the fuel supplyline in the usual manner. In this construction the pressure in the pumpchamber 56during the pressure stroke of the pump plungerlifts the valve50 against the yaction of spring '62, permitting fuel to flow to theengine. Since, however,.the surface area in the rear of the valve whichis exposed to the pressure in the fuel line is almost but not quiteequal to the area exposed to the pressure on the. face of the valve, theupward movement of this member is maintained within predetermined limitseven though the spring 62 is not fully compressed. If now the pressureon the lower face of the valve 5U is decreased by reason of the openingof the spill valve of the pumpplunger during the discharge strokethereof, then the pressure upon the rear face, being momentarilygreater, will act to move the valve in a closing direction. The samemovement, however, tends to withdraw the fuel from the region in therear of the valve and adjacent the fuel supply line 'l so that the firstmovement of any oscillation or reversal Vof direction of ow in the fuelsupply line is in the direction of the valve chamber 60, Whereas thedisplacement in the opposite direction'tends to displace the fuel in thedirection of the pump chamber 56 during the closing movement of thevalve. Should the valve reach its full closed position during the periodin which there is a continued surge of fuel from the line in thedirection of the pump,

. this surge will first tend to dissipate itself in the valve chamber 60and thereafter surge as'a pressure wave in the direction permitted bycross passage 58 and verticalpassages 51, where the pressure Wave havingaccess to a slightly greater area or pressure surface will tend to liftthe valve slightly and dissipate itself through the pump chamber 5B. Inthis structure violent oscillations of the valve 50 are prevented whileat the same time oscillations of the fuel within the fuel supply linewhich normally result in secondary and tertiary injections aredissipated.

It will be apparent that in each of the embodiments of the inventionfree communication is permitted through the system betweenA the seat ofthe injection valve 5 and the by-pass passage 33 the instant thispassage is opened by the lip 34 during the upward movement of the pumpplunger. No motion of any mechanical part is required to eiect orcomplete this communication since the only valve between the pump andthe injection valve is, and remains, in open position at this time. Thisis important since the desired reduction in the static pressure of theline must take place in a period of a few microseconds.

Each of the embodiments of the invention also provide a construction inwhich. a constant residual pressure is maintained in the system yafterthe pressure has been reduced to a predetermined minimum. Thus, incontradistinction to some prior systems which sought to obtain freecommunication between the pump and the nozzle at the instant injectionis terminated by providing a continuous communication at all times, thepresent invention permits such free communication at the desired instantyet prevents communication at times when undesired,

such as during the suction stroke of the pump. Communication between thepump and the rest of the system during the suction stroke would permitfuel to .be withdrawn from the line to the pump instead of from thesuction side of the pump. The pump would thus be totally ineffective asa metering device. The maintenance of the residual pressure in the lineis desirable to prevent rapid evaporation of fuel in the nozzle which isheated from the combustion'space of the engine, and the formation ofvapor pockets the portion of the line close to the nozzle, as

the inertia is overcome and the fuel accelerated toward the pump. Byproviding a reduction in volume in the region of the greatest reductionof pressure the pressure differences along the line are less and the rameffect greatly reduced. Furthermore, since the valve may open againafter its initial closing 4in response to pressure in the lin'e anysecondary surges in the line are dissipated through the pump in the sameway as the initial pressure drop. For this purpose a very slight openingof the valve suiiices. In most prior art systems the drip preventionmeans has tended to increase the surging of fuel in the line rather thandiminish it.

It will also be observed that since lthe closing movement of thedischarge valve is against the.

residual pressure of the line the valve closes gradually and is notslammed against its seat.

While there have been herein described various embodiments of theinvention other embodiments within the scope of the appended claims willbe apparent to those skilled in the art from a consideration of theembodiments shown and the teachings hereof. Accordingly it is desiredthat the appended claims be given a broad interpretation commensurateWith the scope of the invention within the art.

Having thus described the invention, what is claimed as new is:

1. In a fuel supply system an injection pump including a pump cylinder,a plunger reciprocative within said cylinder, said cylinder beingprovided with inlet and discharge ports, means' for relieving thepressure in said pump cham ber in the course of the discharge stroke ofsaid plunger, a discharge valve normally closing said discharge port andoperable by the' pressure in said pump to open said discharge port, afuel supply line leading from said discharge valve, an injector having anozzle oriiice connected to said supply line, a pressure operatedinjection valve for closing said orifice, said discharge valve having apressure area exposed to the pressure in said supply line eiective tobias said valve in an opening direcwhich would also interfere with theaccurate tion, whereby the reversal of flow in said supply line upon therelease of pressure in said pump acts to maintain said discharge valvein open position to vent fuel from said supply line to the pump side ofsaid discharge valve until the pressure in said line drops to apredetermined value below the pressure required to operate saidinjection valve.

2. A rue1supp1y system including m comb/ina;- tion a fuel feedingdevice, a fuel injector, a fuel supply line connecting said fuelrfeeding device and said fuel injector, a valve controlling communicationbetween said fuel feeding device and said supply line, said valve havingsurface area exposed to the pressure in said feeding device when thevalve lsin closed position and being operable by the pressure in saiddevice to open communication between said device and said supply lineupon an increase in pressure in said device and to close suchcommunication in response to a decrease in such pressure, said valvealso having a surface area exposed to the pressure in said line andacting to move said valve in an opening direction in response to apredetermined pressure in said line.

3. A fuel supply system including in combination a fuel injection valveopening in response to the pressure of the fuel supplied thereto and yclosing upon a predetermined decrease in such pressure, a pump, a fuelsupply line connecting saidpump and said injector, a movable memberpositioned between said pump and said injector, said member beingoperable in response to an increase in pressure within said pump to opencommunication between said pump and said sup-- simultaneously increasethe total line in4 proportion to the increase in pressure, means forsuddenly relieving the pressure within said pump, and means associatedwith said movable member for maintaining the same in open position untilafter a predetermined decrease in the pressure within said supply line.

4. A fuel feeding system including in combination a fuel injectiondevice, a fuel pump, a supply line for conducting fuel from said pum'pto said injector, a valve positioned between said pump and saidinjector, said valve having a pressure area exposed to the pressure insaid pump when the valve is in closed position and also having a furtherpressure area exposed to the pressure in said line, said areas beingeffective ply line and to volumetric capacity of said upon predeterminedincreases in pressure in either said pump or said supply line to movesaid valve in an opening direction, and resilient means for biasing saidvalve in a closed direction, whereby predetermined increases in thepressure in said pump cause said valve to open and permit the flow offuel to said injector and whereby pressure in said line acts in anopening direction on said valve to permit the flow of. fuel in a reversedirection upon the decrease in pressure in said pump, therebymaintaining in said line a predetermined pressure below the injectionpressure during periods when the pump pressure is below the injectionpressure.

5. A fuel feeding system includingin combination a fuel injectiondevice, a fuel pump, a supply line for conducting fuel from said pump tosaid injector, a valve positioned between said pump and said injector,said valve having a pressure area exposed to the pressure in said pumpwhen the valve is in closed position and also having a further pressurearea exposed to the pressure in said line', said areas being effectiveupon predetermined increases in pressure in either said pump or saidsupply line to move said valve in an opening direction, resilient meansfor biasing said valve in a closed direction, and means to adjust theDtension of said resilient means, whereby predetermined increases in thepressure in saidl pump cause said valve to open and permit the flow offuel to said injector and whereby pressure in said line acts in anopening direction on said valve to permit the flow of fuel in a reversedirection upon the decrease in pressure in said pump, therebymaintaining in said line a predetermined pressure below the injectionpressure during periods when the below the injection pressure.

6. A fuel feeding system including in combinapump pressure is tion apump-an injector, a fuel supply line between said pump and saidinjector, a pressure responsive valve between said pump and saidinjector controlling the ilowof fuel through said line and operable inone direction to open communication between said pump and said injector,and means associated with said valve for relieving the pressure in saidline when said valve approaches the limit of its opening movement.

7. A fuel feeding system including a pump, an

injector, a fuel supply line between said pump and said injector, apressure responsive valve between said pump and said injectorcontrolling the now of fuel through said line and operable in onedirection to open communication between said pump and said injector,means forming with said valve an auxiliary chamber in restrictedcommunication with said line, whereby upon the increase of pressure uponthe face of the valve the volumetric capacity of said auxiliary chamberwill be proportionately decreased and .upon decreases of such pressurethe volumetric capacity of said auxiliary chamber will be increased inproportion to the decrease in pressure in said line.

8. In combination, a fuel'pump having a pump chamber, a fuel supplylineleading from said trolling ,10. The combination, with a fuel injectionsystem of the type having a fuel injection pump, a closed fuel injectionnozzle and a fuel supply-line connecting said pump and nozzle; of avalve con- -communication between said pump and said nozzle, said valveopening in response to the pressure on the pump side thereof, and alsoopen'- ing in response to pressures above a predetermined value in saidline between said valve and said nozzle said predetermined value beingless than the pressure required vto open said nozzle.

1l. In a system of the type including a high pressure liquid pump, apressure operated atomizing device, and a supply line connecting saidpump and said device, the combination of a valve controllingcommunication between said pump and said device, means to `suddenlyrelieve the pressure on the pump side of said valve, said valve openingin response to pressure on the pump side thereof and remaining open uponthe relief of the pressure on said pump side until the pressure betweensaid valve and said nozzle falls to a predetermined value below thepressure required to operate said atomizing device.

l2. In combination a high pressure liq'uid pump, a pressure operatedatomizing device, a supplyl line providing .a passage between said pumpand said atomizing device, a valve controlling said passage, said valvebeingppened in response to the pressure in said pump, means to suddenlyrelieve the pressure on the pump side of said valve, and means tomaintain said valve in open position upon the relief of pressure onsaidpump side thereof until the pressure'between said valve and saidatomizing device falls to a predetermined value below the vpressurerequired to f operate said atomizing device.

pump chamber, a valve controlling communican tion between said chamberand said supply line, said valve being opened in response to pressure insaid pump chamber, means to suddenly relieve the pressure in said pumpchamber, and means to maintain said valve in open position after therelief of pressure in said pump chamber to vent fuel from said line tosaid chamber until the pressurein said line drops to a predeterminedvalue.

9. In combination, a fuel pump having a pump chamber, a fuel supply lineleading from said pump chamber. a valvecontrolling communication`between said chamber and said supply line, said valve being opened inresponse to pressure in said pump chamber, means tosuddenly relieve thepressure in said pump chamber, and means responsive to the pressure insaid line for holding said valve in open position to vent fuel from saidline to said chamber until the pressure in said line has been reduced toa predetermined value.

LoUIs BEH.

REFERENCES CITED ,The following references are of record in the iile oflthis patent:

UNITED STATES PATENTS Number Name Date 2,211,252 Bremser' Aug. 13, 19401,974,851 Hurst Sept, 25, 1934 2,202,761 Fiedler May 28, 1940 1,589,515Danielsson June 22, 1926 2,007,871 Oldham .1 July 9, 1935 2,247,421 Tabbet al. July 1, 1941 2,033,839 Lawson Mar. 10, 1936 2,019,103 Thege Oct.29, 1935 1,989,720 Thege Feb. 5, 1935 2,131,779 Zwick Oct. 4, 19381,981,913 Fielden Nov. 27, 1934 'FOREIGN PATENTS Number Country Date '60490,741 Germany Jan. 31, 1930 797,444 France Apr. 27, 1936 Switzerland138,400 May 1, `1930

